RFT GC6131 specifications

Category : Cassette decks

Brand : RFT

General

Connections

Tech nical data

Special features

The GC613x series was a further development of the GC603x series to meet the Hi-Fi standard. The drive received an electronically controlled DC motor that runs continuously with the device switched on, but it was not convincing in a vertical installation position (originally designed for horizontal installation in the Geracord GC6010, 6020 and 6030 top loaders), not least due to the exclusive use of plastic parts. The mechanical processing, although the device is robust, is quite poor. Sharp -edged front panel, fixing of the cassette in the cassette compartment insufficient (tilted slightly when the head carrier was retracted), adjustment of the drive switches partly defective (end-of-tape switch-off triggers when the pause button is kept fully pressed in while waiting for a recording), risk of loose contact due to oxidation of the A / W switch mechanically moved by the drive via a metal rail on the circuit board.

The sound head X2C70 was subject to high wear (abrasion).

The robust device could be operated completely manually (no automatic band selection, etc.) and was therefore very popular with disc jockeys.

The recording quality that can be achieved is surprisingly good if it is precisely calibrated to the type of tape (internally on the printed circuit board). From 1990, "West" tapes required new calibration, otherwise extremely high-altitude and pumping effects of the DNR compander due to higher tape sensitivity than with DDR tapes.

Headphone amplifier very powerful, but significant distortions when falling below the minimum headphone impedance of 60 ohms. Simple bridging of the stereo channels on the headphone plug to assess the sound head azimuth setting results in strong distortions due to mutual loading of the output stages of both channels.

Please note: the above data from the original service manual refer to the GDR standard TGL 27616/02 and HiFi according to TGL 28660/04, which was based on the DIN standard. Above all, the frequency responses must not be compared with those of Japan decks, which were often measured at a level of 20 dB below the standard level in order to conceal the band saturation in the highs.

Review in 2017: the present copy is still fully functional, belts and slip clutches are intact original parts, now 30 years old.

Other models of the same series: GC6132, GC6133 These variants were visually adapted to other Hi-Fi components, but were produced only in small quantities.

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RFT -HiFi.de : GC6131

Tech nical data from: Service manual HiFi cassette deck GC6131, VEB Elektronik Gera, Printed matter No. III/29/1 Mn 102/86 (1986)

  • 1 Data
  • 2 Comments
  • 3 pictures
  • 4 Reports
  • 5 Links
  • 6 References
  • Manufacturer: VEB Elektronik Gera (Germany, DDR)
  • Model: Geracord GC6131
  • Type: Stereo cassette deck, shelving unit (HiFi component)
  • Years of construction: 1985 - 1989
  • Manufactured in: Gera (Germany, DDR)
  • Color: Metal case black, front black or silver metallic
  • Remote control: not available
  • Power consumption: 15 W (according to the imprint on the back of the device)
  • Dimensions: 390x130x272 mm (WxHxD)
  • Weight: 4.8 kg
  • Factory price approx.: 1,350 M (DDR)
  • Number of inputs: 4
    • Audio/Tape (5-pole. DIN socket, current sink, sensitivity 0.5mV /kOhm source resistance, requires about 150-500 kOhm series resistance in the input device or in the cable, otherwise overdriving the input amplifier even before the recording level controllers)
    • Phono (5-pole. DIN socket, without equalizer amplifier, for high-impedance ceramic scanners, sensitivity 500 mV at 1 mOhm load)
    • 2x microphone (5-pole. DIN jack separated for left and right channel, sensitivity 0.6mV, >6 kOhm )
  • Number of outputs: 2
    • Audio/amplifier (5-pole. DIN jack, also used as audio/tape input, output > 500 mV at load >= 10 kOhm at reference level)
    • Headphones (5-pole. "Cube"-DIN socket, >= 3 V at load impedance >= 60 ohms)
  • Audio/Tape (5-pole. DIN socket, current sink, sensitivity 0.5mV /kOhm source resistance, requires about 150-500 kOhm series resistance in the input device or in the cable, otherwise overdriving the input amplifier even before the recording level controllers)
  • Phono (5-pole. DIN socket, without equalizer amplifier, for high-impedance ceramic scanners, sensitivity 500 mV at 1 mOhm load)
  • 2x microphone (5-pole. DIN jack separated for left and right channel, sensitivity 0.6mV, >6 kOhm )
  • Audio/Amplifier (5-pole. DIN jack, also used as audio/tape input, output > 500 mV at load >= 10 kOhm at reference level)
  • Headphones (5-pole. "Cube" DIN socket, >= 3 V at load impedance >= 60 ohms)
  • Sound heads: 1 recording/playback, 1 RF quenching head
  • Quenching/premagnetization frequency: approx. 83 kHz
  • Motors: 1
  • Synchronisation fluctuations: <= 0,18 %
  • Deviation of the mean band speed from the setpoint: <= +/- 1.5%
  • Band types: Type I, II and III (FeCr)
  • Frequency response: 35 ... 12500 Hz (Fe2O3 Type I band), 35...14,000 Hz (CrO2 Type II band), 35...14,500 Hz (FeCr Type III band)
  • Total harmonic distortion: K3 <= 3%, K2 <= 2%
  • External voltage range: for all band types without noise reduction >= 45 dB, for Cr/FeCr with DNR compander: >= 48 dB
  • Noise voltage range: Type I 48 dB without NR / 51 dB with dyn. Low-pass filter "RVS" / 56 dB with compander "DNR" type II 50 dB without NR / 54 dB with dyn. Low-pass filter "RVS" / 58 dB with compander "DNR" type III 55 dB without NR / 62 dB with dyn. Low-pass "RVS" / 67 dB with compander "DNR"
  • Crosstalk attenuation (1 kHz): >= 30 dB
  • Cancellation attenuation >= 65 dB
  • Sidetrack attenuation (1 kHz): >= 60 dB
  • Auto-reverse: not available
  • Title search: not available
  • Dolby: Dolby B compatible noise reduction system "DNR"
  • MPX filter: yes, switchable
  • Recording level control: 2 rotary controls separately for left and right channel
  • Pitch control: not available
  • CD synchro recording: not available
  • mechanical 3-digit tape counter with zero stop function out of all tape running functions (Memory)
  • LED level indicator (2x10 LED)
  • Rec Mute button (function for inserting pauses, button locks in)
  • Noise reduction system "RVS" (only on the playback side, attenuates high frequencies depending on the level)
  • Noise reduction system "DNR" (compander system, Dolby-B compatible


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RFT GC6131 relate